CSS去掉select默认样式

<div class="dropdown-selection">
     <select  class="select-option">
          <option value="file">{{t.file}}</option>
          <option value="hot">{{t.hot}}</option>
          <option value="mold">{{t.moldid}}</option>
          <option value="sign">{{t.register}}</option>
          <option value="time">{{t.time}}</option>
      </select>
</div>

.dropdown-selection {
  display: block;
  width: 220px;
  margin: 0 auto;
  height: 60px;
  line-height: 60px;
  font-size: 28px;
  box-sizing: border-box;
  cursor: pointer;
  position: relative;
  &::after {
    content: ' ';
    position: absolute;
    right: 6px;
    top: 50%;
    margin-top: -5px;
    width: 0px;
    height: 0px;
    border-left: 10px solid transparent;
    border-right: 10px solid transparent;
    border-top: 10px solid #fff;
    font-size: 0px;
    line-height: 0px;
  }
  .select-option {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    position: relative;
    outline: none;
    border: 0 none;
    position: relative;
    padding: 0 0 0 5px;
    width: 100%;
    color: #fff;
    background: none;
    background-color: transparent;
    font-size: 28px;
    z-index: 99;
    overflow: hidden;
  }
  &.back-after {
    width: 240px;
    margin: 0 30px 0 0;
    &::after {
      border-top-color: #666;
    }
    .select-option {
      color: #666;
    }
  }
  &.filter-search {
    width: 150px;
    margin: 0;
  }
}